Identify which of the following statements regarding water logging are true.

Statements:

a. A land is said to be water logged when the pores of soil within the root zone of a plant get saturated and the normal growth of the plant is adversely affected due to insufficient air circulation.

b. The problem of water logging occurs mainly due to the rise of the ground water table beyond permissible limits.

c. Rainfall is the major contributing factor to the natural causes of water logging.